Steam generation.



vJ. E. FLETCHER.

STEAM GENERATION.

111221110111011 num nu e, 1911. 998,568. Patented July 1s. 1911.

y x 5 @W COLUMNA PLANMRAPH co., wAsHlNuToNhD. c.

J. E. FLETCHER. STEAM GENERATION. APPLIOATION FILED MAY s, 1911.

998,568. 'Patented July 18,1911.

2 SHEETS-*SHEET 2.v

CQLUMBIA PLANOURAPH CO.. WASHINGTON. D. C.

JOSEPH ERNST FLETCHER, 0F DUDLEY, ENGLAND.

STEAM GENERATION.

aaaaos.

Specification of Letters Patent.

Patented July 18,` 1911.

Application filed May 6, i911. Serial No. 625,645.

To alt whom it may concern:

Be it known that I, Josnrrr ERNST FLn'roi-rnn, a subject of the King ofEngland, residing at Dudley, in the county o-f forcester, England, haveinvented certain new and useful Improvements in or Connected with SteamGeneration, of which the following is a specification.

rThis invention has reference to the generation of steam, and has forits objects and etl'iects, among others, to provide improve ments bywhich a battery or plurality of separately heated steam generators willwork together', and evaporate water at a uniform rate, and alsoevaporate a greater quantity of water in a given time; and at the sametime priming and scaling in boilers or steam generators will bediminished, and unequal strains prevented; while other effects areaccomplished, as hereinafter specified.

In the following description of steam generating plant, the improvementshereunder are comprised.

The battery or plurality of boilers employed in a plant has a commonwater level, and the feed water is supplied by the pump or other forcingmeans, to one (or may be two) of the steam generators of the battery;while the water to the other steam generators is conveyed from this (orthese) by a pipe to the other steam generators; and th-e water level ismaintained at a common level in all the steam generators by means ofthis pipe or pipes, which connects them all up, and at the requiredlevel. This common level is thus obtained by gravitation wholly, or itmay be partly by gravitation. The whole battery is thus put into steamand water equilibrium by the feed and the steam ranges, and maintainedat a uniform tem perature.

The feed water may be previously heated, or cold, and introduced intothe steam generator at the usual level, or by means of a spray or thelike into the steam space. All the generators will be connected by acoinmon steam pipe or drum.

lWhen a heavy call for steam, as frequentlv happens, is made on abattery arranged and adapted to operate as described, a ready reply isgiven, for when a sudden is produced to meet the case; while under usualconditions of a battery of steam generators, one or more of them in agroup will steam more freely than the others, and although connected incommon bv a large main or steam drum, the effect of onel or more badlysteaming' generators is to bring about a general lowering of pressure,accompanied by priming, and wet steam, this being the result generallyof local drop in temperature; but by the improvements under viated.Further, by the improvements, an increased rate of evaporation isobtained throughout the battery, so that the number of boilers in abattery can be diminished.

ln the accompanying drawings, the application of the invention inseveral slightly modified manners to batteries of steam generators isillustrated; and the invention will be further described in connectionwith these applications and illustrations, their description being takenin the order of the tigures.

Figure 1 is an elevation of a battery of steam generators, illustratingmy invention. Eig. 2 is a similar view of a slightly modified form ofthe invention. Fig. 3 is an elevation of a battery of multi-tubularsteam generators, illustrating my invention in connection therewith.Fig. a is an elevation illustrating the invention applied to steamgenerators of the water tube type. Fig. 5 is a side elevation of thesame, the feed boiler being' shown in section. Fig. 6 is a view similarto F ig. 5, but showing a slightly modified arrangement. Fig. 7 is anelevation of a battery of steam generators, illustrating another form ofthe invention. F ig. 8 is a detail view of a steam generator, and amodification of the invention.

Generally, throughout the different ligures, the same letters andligures of reference are used to denote the same or corresponding partswherever they occur.

The water heating and steam generating generator, that is, the one intowhich the feed water to be evaporated is first introduced, prior to itsdelivery to the others of this invention, these defects are obthe saidgenerators or battery, is designated a, while the other generators aredesignated ZJ.

is the pipe by which all the feed water is supplied to the heatergenerator a-which for convenience may be called the feedboiler Z is thepipe by which the water at the temperature of steam generation in thisgenerator is taken off from it, after having passed through it, and beenheated in it; and e is the main pipe connected with the other severalgenerators Z), which conveys this Water to them.

1With regard to Fig. l, which illustrates one application of theinvention to a set or battery of Lancashire or like type of steamgenerators, the manner of the working of this system is as follows:-All, or the greater portion of the feed water to be sup-- plied to thebattery of steam generators is delivered by the pipe c from the feedpumps or other forcing apparatus, into one part of the feed-boiler a.;and in this case, it is delivered at a point near the water level a?,that is, slightly below it, as indicated in full lines. In thisfeed-boiler, which generally is of the same construction as the othersteam generators, the feed water is heated by fuel ,of any suitablekind, burned 1n the furnaces f, and steam is generated from it; hencethis feed-boiler serves in the capacity of one of the steam generatorsof the battery, as well as a feed water heating boiler; the steam fromit being conveyed to the main steam supply pipe z' of the battery,through the pipe It. Thus the water .in this steam generator orfeed-boiler will be, at least, at a temperature corresponding with thatdue to the pressure of steam employed in and supplied by the plant. Thewater atthis temperature will be taken away from this feed-boilerthrough the pipe cl at a suitable point, such as shown by the drawing,and delivered into the feed main through e, whence it is conducted bythe connecting branches g, to the several steam generators Z); and incases where suitable, the levels of the outlet from the feed-boiler a,and the point of inlet of the pipes g to the generators Z), will besubstantially the same, so that the water would flow by gravity into theseveral boilers Z) automatically; and its level will be maintained atpractically a constant point throughout the whole, so that they will allwork under practically equal conditions.

In some cases-and it may be in the majority of cases-the working of thesystem by gravity as just referred to, could not be sutlicientlysatisfactorily accomplished; and, therefore, in such cases, there isintroduced between the feed-boiler a and the feed distribut-ion main efor. forcing the hot feed water, a pump, shown in Fig. 8, and marked70,' and this pump would simply force the hot water delivered to itthrough the pipe (l into'the main e; and so that under any conditions,the levels of the water in the several steam generators Z) :an be keptat a constant, and at the required point. Or, the. flow of water bygravity from the feedboiler a, to the generators t), may be ell'ected orassisted by keeping the water level in the feed-boiler, at a somewhathigher level than the working level in the steam generators Z). Suitablevalves or cocks j can be provided for the purpose of regulating the fiowof water through these pipes, or closing or regulating them, in case ofneed.

The modified arrangement shown in Fig. 2 is the same as that shown inFig. l, with the exception that in addition to the pipes (l, whichcommunicate with the main distribution hot water feed main c, there areadditional pipes (Z1, which couple the several steam generators a` andt), as shown; the object and effect being to assist in the preservationof the common water level in the gene "ators of the battery. That is tosay, the feed water supplied through the pipes c to the feed-boiler cwill pass to and through it, similarly as above described in connectionwith Fig. l; and then this water, or some of it, can pass by way of thepipe (Z into the feed main c, while another portion of it can passdirect into the next steam generator L, by the connecting pipe d1; and.similarly, the steam generators b are counected together by means ofhorizontal connecting pipes f/l, near the water level, as well as to thefeed main c, by the pipes y. ln such a system, the valves y' are more orless closed, or wholly closed, accordiiig to whether it is desired touse the common feed pipe c for supplying the several steam generators Z)with feed water from this main` or otherwise. In this modification thereis also provided a pipe m, connecting the feed water pipe c with thedistribution feed main e, and having upon it cock n, by which more orless vater may, if desired, be permitted to pass directly from thesupply or feed pipe f', connected with the feed-boiler o, into thedistributing feed .main e, at such a rate, and in such a quantity, asmay be found necessary or desirable, so as to facilitate the keeping ofthe water level in all the boilers uniform, or for other purposes.

ln Fig. 3 is shown an application of the invention in connection with a,battery or plant of multi-tubular or marine type of steam generators. lnthis case, the feed water from the feed pipe f: is delivered to thefeed-boiler at a point below the tubes; while the water to be deliveredto the steam generators is taken olf by the internal portion of the pipe(l, near the, .surface of the water; and in this arrangement also, thegenerators 7) are fed with water from the feed main c, by a feed pipe y,at each side of each of them. In this application also` an auxiliarypipe m, and cock n, are prol lt.

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vided between the feed pipe c and steam generators Z), similarly, andfor the saine pui-pose as set forth with reference to Fig. 2.

lFigs. l and 5 show the invention applied to steam generators of thewater tube type, in which a water and steam drum is disposed over thenests or groups of water` tubes; and Fig. G shows a slightly modiedarrangement of this. In this case, t-he water is fed to the first steamand water drum of the feed-boiler a, similarly as in the other casesabove; and from it, it is led by the pipe il to the feed main e, anddelivered from it into the steam and water drums of the boilers by thepipes g. In this case, in order to promote the circulation, and theefficient heating of the feed water in the feed-boiler a, the feed orinlet pipe c may be led directly across the steam water drum (see Fig.5), and carried down into one or more of the down pipes y), which leadto the lower tube headers, so that the water would pass into thewater-tubes of the generators, and thence by the upper header' into thewater and steam drum; and from this drum, it will pass into an internalportion of the pipe d, the inlet orifice of which ivould be near thewater level ai, and be deliver-ed to the feed main c. Or, instead ofthis arrangement, the feed water may be delivered into the feed-boiler cby way of the chamber g, which is commonly called a mud drinn, as showniii Fig. 6, whence it would pass through the water-tubes and upperheader as just described, and then by way of the pipe (Z, be deliveredto the feed main c. From this main, the water would pass into etch ofthe other generators 7), by way of their mud drums headers and tubesinto the upper steam and water drums.

ln the system of steam generation concerned, in order to obtain themaximum efficiency, it is very important that the water when deliveredinte the steam` generators from the one (or more) of them, in which allthe water to be converted to steam is introduced, is at the steamtemperature of it, that is, at its minimum density, and also that theproper or required water levels in the genere ators fed from the feedsteam generator', should be maintained. 1n order to obtain theseconditions, it is necessary that the pressure and temperature in thefeed steam generator should be capable of being controlled andregulated; and this is effected by the employment of a pipe r, shown inFig. 7, which may be termed a balancing pipe, interposed, and formingcommunication between the steam space of the feed generator e', and oneof the other generators Y; of the battery; and it has in it, a pressureregulating valve s of any known suitable type, such as the loadedself-acting, or otherwise.

,fall the steam generated in the feed steam generator a passes by thebalancing pipe fr to the steam generator Z) which it communicates with;while the steam from the latter. and the rest of the steam generators,passes to the steam main By this means, if the valve s on the balancingpipe r be loaded, or regulated to choke the escape of steam from it, thepressure, and teniperature of the water and steam in the feed generatora, can be regulated, and held higher than those in the other steamgenerators Z).

The feed water pipe d from the feed steam generator ai, to the feedwater main e, may also, in some cases, be fitted with a pressureregulating valve, which may work either automatically, or be set byhand, and thus this plus or ext-ra pressure and temperature in the feedgenerator will insure that the feed water entering the steam generato-rsL of the battery, from the feed steam generator a, will be at the steamtemperature of those generators; and that the proper or required levelsin these boilers will be maintained at all times.

A modified manner of promoting the better feeding of the generators Z)with water from the feed-boiler cz., may be effected by providing on thesteam pipe /i from the feed-boiler a, a loaded valve h?- of the steamreducing type, of any known kind (shown in Fig. S), so that a higherpressure in u, may be maintained. As an instance of where this may bemore serviceable, the case where the feed-boiler a is placed at a lowerlevel than the steam generators Z), is one.

4VV ith regard to the chief points of ditferentiation between thepresent system and invention, and other systems, of working steam powerplant, wherein a plurality or battery of steam generators are employed,in these former systems, frequently, feed `water heaters are interposedbetween the `feed water pumps or machinery, and the steam generators, inand by which the feed water 1s heated by the products of combustion offuel, or by steam; and in some of such cases, this feed water heatingmechanism consists of apparatus known as fuel economizers which consistgenerally of nests or groups of water tubes through which the feed wateris made to pass on its way to the steam generators, and so ai ranged andplaced as to absorb heat into the feed water; while in other cases,there has been proposed to be employed a separate boiler working at highpressure, and in which the water is boiled by burning fuel on a grate insame, and from which the hot. water at or above the pressure of that ofthe steam in the steam generators to be supplied with hot feed water, istaken and delivered to said steam generators; but in the latter easethis feed water boiler has had no steam taken from it, and it has notconstit-uted therefore one of the steam generators of the battery orplant for supplying steam for power. In 'other cases again, both a feedWater heater and a fuel economizer are used in the manner referred to.The objects of these contrivances have been to increase the temperatureof the feed Water before it enters the steam generator, in order that itshall be more readily converted to steam in them, and also to diminishthe quantity of fuel for evaporating a given quantity of Water; butunder the present invention, before being delivered to all the steamgenerators, the feed Water is first introduced into a primary apparatus,Which, in itself, is a steam generator, as Well as a Water heater, andwherein the heat is applied to the Water by the direct combustion offuel in the furnaces of this steam generator; and not only is the Waterheated, but steam is also generated, and it constitutes in effect one ofthe several of the steam generators which constitute the battery; and,moreover, the feed Water Which is fed to this feedboiler, as it istermed, may already be hot, having been preheated bv first passing itthrough the feed Water heater or economizers of the kind just referredto; in which case, of course, the feed-boiler is employed in addition tothe preliminary or ordinary feed Water heaters or economizers.

In the feed-boiler or primary generator, under this invention, theheating of the feed Water it will be seen is pushed to the point Whereit is raised, at least, to the temperature corresponding ivith that dueto the pressure at which steam is required to be produced in, anddelivered from the power plant; so that steam is actually raised in it,and led away into the common steam supply main. And, as above stated,the pressure of this steam generated in the feed-boiler may be the sameas that in the other steam generators of the plant, to Which the Wateris being fed, and before it-the feed Wateris fed into said generators.

ln the cases illustrated in the drawing, the primary steam generator orfeed-boiler a is of the same form and size practically as the others ofthe battery or plant; but in special eases, or Where desired, thisfeedboiler may be of a construction other than those constituting themain steam generators, to which the feed Water from this primary orfeed-boiler is led; but it (or they, if more than one be used) must beof suflicient size or heating capacity to not` only raise thetemperature of the Whole of the feed Water passing to the Whole of thebattery of boilers, to Which it is applied, to the boiling point orhigher) of the Water, corresponding With the pressure of steam beinggenerated by the battery, but must in addition be capable of generatingsome steam at that (or a higher) pressure from the feed Water, Whilepassing through it to the battery; the steam so generated passingdirectly (or through a steam reducing valve) into the steam main commonto the battery or plant. By thus feeding into a battery of steamgenerators only water which is at the same as, or a higher temperaturethan the Water in these generators, and at which temperature steam isbeing generated, their duty is confined almost entirely to thegenerating of steam from such water; they being relieved from the dutyof raising the Water to the temperature atl which steam is liberatedfrom it. Also, by thus raising the temperature of the feed Water in thefeed boiler to a point corresponding with, that. from Whichisteam isbeing generated in the other steam generators of the plant or battery, avery large proportion of the scale forming matter carried by the feedwater into the feed boiler is deposited in it, and thus the hot feedWater passing into the steam raising generators from the feedboiler isrelieved to a very large extent of scale forming matter, and very littlescale is deposited in these steam raising generators; which are thusable to work more eiiiciently, and are less liable to expansion orcontraction strains than would otherwise be the case; and in a largemeasure, in cousequence, a greater quantity of water is evaporated fromthe generators in a given time under this system, than if fed with Waterin the usual Way, other conditions being the same. Or, for a givenamount of water evaporated in a given time, less fuel is required.

What is claimed is 1. The method of generating steam in a plurality ofsteam generators, consisting in introducing all the Water from whichsteam is to be generated in the said generators, into one steamgenerator (or it may be more) of the set, and heating it therein by fuelburned therein, and at the same time generating steam from it in saidgenerator (or generators), which steam constitutes a part of the steamgenerated by the battery for power or other purposes; and withdrawinglthe Water from said generator (or generators) at the temperature ofsteam generation, and delivering it to the others of said set ofgenerators, wherein it is separately heated by fuel burned therein; forthe purposes specified.

2. The method of generating steam in a plurality of steam generators,consisting in introducing all the Water from Which steam has to begenerated in the said generators, into one steam generator (or it may bemore than one) of the set. and heating it therein by fuel burnedtherein, and at the same time generating steam from it in said generatoror generators and maintaining such steam at a pressure higher than thatin the other steam generators of the battery, and conveying this steaminto the steam space of another of said steam generators, and With- Intestimony whereof I have signed my drawing the Water from said feedgenerator neme to this specification 1n the presence of or generators atthe temperature of steam two subscribing Witnesses.

generation therein, and delivering,` it to the JOSEPH ERNST FLETCHER.others of said set of generators, and wherein Witnesses:

it is converted to steam hy fuel burned WILLIAM TROATH,

therein; substantially as set forth. VILLIAM HENRY HILL.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

